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山元　一広

KAGRAの低温懸架系

2015 December 18平成 27年度東京大学宇宙線研究所共同利用研究成果発表会

@東京大学柏キャンパス , 柏市、千葉

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0. Abstract

Here, I explain 1.Cryostat installation at KAGRA site2.Cryogenic payload 3.Sapphire suspension

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Contents

1. Introduction2. Cryostat installation3. Cryogenic payload4. Sapphire suspension 5. Summary

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1. Introduction

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3km3km

MozumiY-end Sakonishi

X-end

AtotsuCenter

Vibration isolation system (Type A), Cryocooler unit, Cryostat, Cryogenic payload

Schematic view of KAGRA interferometer Four mirrors of arm cavity will be cooled.First km scale cryogenic interferometer

Kamioka mine (Underground site)

1. Introduction

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Thermal noise : Fundamental noise

Suspension thermal noise :

mirror position fluctuation

(vibration of suspension for mirror)

Mirror thermal noise : mirror surface fluctuation

(elastic vibration of mirror itself)

1. Introduction

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Fluctuation-Dissipation Theorem

Relation between thermal noise

and mechanical loss in suspension and mirror

Amplitude of thermal noise is proportional to

(T/Q)1/2.In general, Q (inverse number of magnitude of dissipation) depends on T (temperature).KAGRA sapphire mirror is at 20K.

1. Introduction

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3rd generation : 10 times better sensitivity

Cryogenic techniques will be adopted.

Einstein Telescope (Europe), Voyager (U.S.A.)

Einstein Telescope

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to SAS

View ports

Remote valve unit

4 Low vibration cryocooler unit

Main LASER beam

Cryostat Stainless steel t20mm Diameter 2.6m Height ~3.6m M ~ 10 ton

Cryo-coolers Pulse tube, 60Hz 0.9 W at 4K (2nd) 36 W at 50K (1st)

Outline of cryostatCryogenic

payload

Mirror

1. Introduction

S. Koike

1. Introduction

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Pulse tube cryocoolers

Pulse tube cryocoolers

Sapphire suspension

Sapphire mirror (About 20K)

Sapphire fiber

Cryo-payload

Schematic view of cryostat and cryo-payload

1. Introduction

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Pulse tube cryocoolers

Pulse tube cryocoolers

Schematic view of cryostat and cryo-payload

Cryo duct for 300 K radiation

2. Cryostat installation

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Installation of cryostat is a hard mission !

Cryostats are carried along 3 km tunnel !

12BS

3 km

3 km

IXC

IYC

EYC

EXC

Assembled Cryostat Photos

EYC

N. Kimura

All four cryostats were installed.

2. Cryostat installation

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Cryo ducts are connected to two cryostats in the center room.

Progress of the cryostat assemble;

•EXC & EYC were assembled as vacuum vessels

without duct shields and cryo-coolers

from the end of 2014.11 to the end of 2015.1.

•IYC & IXC were assembled with all of components

such as duct shields and cryo-cooler units

from the end of 2015.2 to the mid of 2015.4.

EYC

EXCIXC

IYC

• Duct Shield

• 12 mL vacuum duct

• 6 mL +6 mL vacuum

duct

• Cryostat

• Gate Valve

BS

3 km

3 km

Cryo-cooler unit installation

N. Kimura

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Outline of vibration isolation and cryostat

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Pulse tube cryocoolers

Pulse tube cryocoolers

3. Cryogenic payload

Vibration isolation, adjustment, control, damping, …

Cryo-payload

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Design

Almost all parts were designed.

A. Hagiwara

3. Cryogenic payload

3. Cryogenic payload

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Prototype test of cryogenic payload

Cooling test on December

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“Sapphire monolithic lop-eared suspension”

One of the most importantparts of KAGRA : Main sapphire mirrorsare included.

All parts are made from sapphire.

Sapphire lop-eared suspension

4. Sapphire suspension

fiber break

Hydroxide Catalysis Bonding

Full size suspension as prototype

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Sapphire cylinder with flat cuts as dummy mirror

Blade spring

4. Sapphire suspension

Ears

Fibers with nail head

Full size suspension as prototypeAll sapphire parts for full size prototype have already been delivered (IMPEX and Shinkosha).

202020202020202020

Jigs to assemble full size prototype is being prepared.

4. Sapphire suspension Full size suspension as prototype

Some parts were delivered.

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Measurement of shape of sapphire bulk and earsFor precise position of ears, the geometrical shape and ears were measured (by K. Enami, Mechanical Engineering Center, KEK).

4. Sapphire suspension Full size suspension as prototype

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5. Summary Cryostat installation All four cryostats were installed ! Connection to cryo duct are in progress.

Cryogenic payload Almost all parts were designed. Cooling test of prototype will be started soon !

Sapphire lop-eared suspension All sapphire parts for full size prototype are delivered. Assembly jig for full size prototype are being prepared.

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KAGRA Cryogenics Group

Toshikazu SUZUKI EO and SEO member KEK, Senior Fellow

Nobuhiro KIMURA Cryostat sub-chief KEK, Assoc. Prof.

Kazuhiro YAMAMOTO Cryo-Payload sub-chief ICRR, Assist. Prof.

Takayuki TOMARU Chief KEK, Assoc. Prof.

Tatsuya KUME Surveying, Alignment KEK, Assoc. Prof.

Rahul KUMAR Simulation, Payload KEK, PD

Ayako HAGIWARA CAD KEK, Technical Staff

Shinichi TERASHIMA Machining KEK, Technical Staff

Iwao MURAKAMI Welding, Assembly KEK, Technical Staff

Hiroki TANAKA Cryo-Payload, Q ICRR, Grad. Student

Takahiro MIYAMOTO Cryo-Payload ICRR, Grad. Student

Suguru TAKADA Cryogenics NIFS, Assist. Prof.

2015.Oct.16

By T. Tomaru(Revised by K. Yamamoto)

Kieran CRAIG Payload ICRR, PD

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Acknowledgement

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Supported by

Mechanical Engineering Center, KEK

Machine shop, The Institute for Solid State Physics, The University of Tokyo

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Thank you for your attention !

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Acknowledgement

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ELiTES: ET-LCGT interferometric Telescope Exchange of Scientists Grant for collaboration about cryogenic between KAGRA and ET European 7th Framework Programme Marie Curie action (Mar. 2012 - Feb. 2017) European people can visit Japan for KAGRA.

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Acknowledgement

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1st : 3 Oct 2012

2nd : 4 Dec 2013

ELiTES meeting

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Acknowledgement

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3rd : 9 Feb 2015

4th : 2 Dec 2015

ELiTES meeting